1. Field of the Invention
The present invention relates to a cartridge, which receives therein fluid material such as mayonnaise, toothpaste and calking agent and a dispensing apparatus such as a dispensing gun for discharging the fluid material from the cartridge.
2. Description of the Related Art
The conventional cartridge of this kind is provided with a tubular receiver xe2x80x9caxe2x80x9d having a cylindrical shape, a cap member xe2x80x9cbxe2x80x9d disposed at the front end of the tubular receiver xe2x80x9caxe2x80x9d and a plunger xe2x80x9ccxe2x80x9d disposed in the tubular receiver at its rear end portion so as to be slidable therein, as shown in FIG. 21. The cap member xe2x80x9cbxe2x80x9d has an outlet opening xe2x80x9cb1xe2x80x9d formed in the middle of the cap member xe2x80x9cbxe2x80x9d. The above-mentioned outlet opening xe2x80x9cb1xe2x80x9d is closed by means of a thin sealing member xe2x80x9cdxe2x80x9d. The inner cavity of the tubular receiver xe2x80x9caxe2x80x9d between the cap member xe2x80x9cbxe2x80x9d and the plunger xe2x80x9ccxe2x80x9d is filled with fluid material.
When the fluid material is discharged from the above-described cartridge, a single set or a plurality of sets of slits xe2x80x9cd1xe2x80x9d having a cross-shape is previously formed on the sealing member xe2x80x9cdxe2x80x9d, as shown in FIG. 23. Such a cartridge is fitted in a dispensing apparatus (not shown) such as a dispensing gun. Then, actuation of a piston (not shown) of the dispensing apparatus moves the plunger xe2x80x9ccxe2x80x9d toward the cam member xe2x80x9cbxe2x80x9d. As a result, the fluid material received in the tubular receiver xe2x80x9caxe2x80x9d is discharged outside through the slits xe2x80x9cd1xe2x80x9d.
When the plunger xe2x80x9ccxe2x80x9d moves to discharge the fluid material from the tubular receiver xe2x80x9caxe2x80x9d, a frictional resistance, which is caused between the outer peripheral surface of the plunger xe2x80x9ccxe2x80x9d and the inner surface of the tubular receiver xe2x80x9caxe2x80x9d, generates a relatively large pressing force applied to the tubular receiver xe2x80x9caxe2x80x9d in the longitudinal direction thereof. Accordingly, it has been conceivable that the tubular receiver xe2x80x9caxe2x80x9d would be collapsed in the longitudinal direction or buckling thereof would occur. In view of such an aspect, the conventional tubular receiver xe2x80x9caxe2x80x9d is formed of cardboard having a high rigidity. For example, the tubular receiver xe2x80x9caxe2x80x9d is prepared by rolling a piece of cardboard into a cylindrical shape, placing the one side edge of the piece of cardboard on the other side edge thereof and securing these side edges to each other by means of adhesive.
It is however difficult to collapse the tubular receiver xe2x80x9caxe2x80x9d of the cartridge having the above-described structure in a small size due to the high rigidity of the tubular receiver xe2x80x9caxe2x80x9d, after the cartridge has served completely (more specifically, the fluid material has been discharged to be used up). This may lead to an enormous waste amount of tubular receivers xe2x80x9caxe2x80x9d of the cartridges, causing social problems of waste disposal. In addition, a gap xe2x80x9cSxe2x80x9d is formed between the inner peripheral surface of the tubular receiver xe2x80x9caxe2x80x9d and outer peripheral surface of the plunger xe2x80x9ccxe2x80x9d in the vicinity of the joined portion of the piece of cardboard, as shown in FIG. 22. The maximum depth of the gap xe2x80x9cSxe2x80x9d (i.e., the distance in the diametrical direction of the tubular receiver xe2x80x9caxe2x80x9d) is relatively large and equal to the thickness of the piece of cardboard forming the tubular receiver xe2x80x9caxe2x80x9d. This may lead to leakage of the fluid material through the gap xe2x80x9cSxe2x80x9d, thus causing a problem. Such a leakage problem may remarkably occur when pressure is applied to the fluid material received in the tubular receiver xe2x80x9caxe2x80x9d through movement of the plunger xe2x80x9ccxe2x80x9d.
An object of the present invention is therefore to provide a cartridge for fluid material, which permits to discharge the fluid material in an appropriate manner when the cartridge is used, on the one hand, and to be collapsed in a small size, after the fluid material has been used up, on the other hand, and a dispensing apparatus for such a cartridge.
After extensive studies carried out by the present inventors to solve the above-mentioned problems, the following findings were obtained:
(1) even when the tubular receiver is formed of a thin film having a low rigidity, the tubular receiver filled with the fluid material provides a relatively large rigidity to bear force generated due to movement of the plunger;
(2) especially, when the fluid material includes fat and oil as in mayonnaise, such fat and oil reduce a frictional resistance between the inner surface of the tubular receiver and the outer surface of the plunger, thus decreasing the pressing force applied to the tubular receiver in the longitudinal direction due to the movement of the plunger; and
(3) consequently, the tubular receiver, which is formed of a thin film, can sufficiently bear the pressing force applied by the plunger, without causing collapse or buckling of the tubular.
The present invention was made on the basis of the above-mentioned findings. In order to attain the aforementioned object, a cartridge of the present invention for fluid material, comprises:
a tubular receiver provided at its front end portion with an outlet opening; and
a plunger disposed in said tubular receiver at its rear end portion so as to be slidable therein,
wherein:
said tubular receiver is formed of a thin film.
The tubular receiver may be provided on its outer peripheral surface at a rear end thereof, in which the plunger is fitted, with a reinforcement member having a ring-shape.
The tubular receiver may be provided on its inner peripheral surface between the rear end portion thereof and the plunger with a reinforcement member having a ring-shape.
The tubular receiver may be provided on its outer peripheral surface at a rear end thereof with at least one stopper member, said stopper member projecting outwardly in a diametrical direction of the tubular receiver. The above-mentioned stopper member may be formed into a ring-shape.
The cartridge of the present invention may further comprises an outer tube having rigidity, into which said tubular receiver is to be detachably inserted from the front end portion thereof, said outer tube having an end, which is to be brought into contact with said stopper member of said tubular receiver so as to prevent said tubular receiver from moving relative to said outer tube in a direction from the rear end portion of said tubular receiver toward the front end portion thereof.
The tubular receiver may have on its outer peripheral surface a plurality of reinforcing ribs extending in a longitudinal direction of said tubular receiver, each of said plurality of reinforcing ribs having opposite ends, which are connected to the rear end portion and the front end portion of said tubular receiver, respectively, so as to prevent said tubular receiver from being collapsed in the longitudinal direction thereof. The opposite ends of each of said plurality of reinforcing ribs may be detachably connected to the rear end portion and the front end portion of said tubular receiver, respectively.
The tubular receiver may taper off from the rear end portion thereof to the front end portion thereof.
A dispensing apparatus of the present invention for a cartridge for fluid material, said cartridge comprising a tubular receiver provided at its front end portion with an outlet opening and on its outer peripheral surface at a rear end thereof with at least one stopper member projecting outwardly, and a plunger disposed in said tubular receiver so as to be slidable therein, said dispensing apparatus comprises:
a support section for supporting said cartridge; and
a piston for moving said plunger of said cartridge from a rear end side thereof toward a front end side thereof to discharge the fluid material received in said tubular receiver from the outlet opening,
wherein:
said support section has a restricting portion, which is to be brought into contact with said stopper member of said cartridge so as to prevent said cartridge from moving in a direction from the rear end side of said cartridge to the front end side thereof.
The restricting portion of said support section may have a tubular shape so that said tubular receiver of said cartridge can be inserted from the front end portion thereof into said restricting portion; and the restricting portion may be swingably supported on said support section around an axis perpendicular to a longitudinal direction of said cartridge.